我有我的应用程序的页面，只包括一个Card用于保存Column在其末端是一个MaterialList。即使我的列表中只有一个或两个项目，该卡也会将其垂直空间扩展到屏幕底部，而不是停在列表项的末尾。该列的文件表明，这是正常的行为列（“布局每个孩子一零或零弹性系数（例如，那些不展开）与无界垂直约束”）。我以为将列表换成a
Flexible可能会达到我想要的效果，但是当我尝试时出现以下错误：

RenderFlex children have non-zero flex but incoming height constraints are unbounded.
I/flutter (11469): When a column is in a parent that does not provide a finite height constraint, for example if it is
I/flutter (11469): in a vertical scrollable, it will try to shrink-wrap its children along the vertical axis. Setting a
I/flutter (11469): flex on a child (e.g. using a Flexible) indicates that the child is to expand to fill the remaining
I/flutter (11469): space in the vertical direction.
I/flutter (11469): These two directives are mutually exclusive. If a parent is to shrink-wrap its child, the child
I/flutter (11469): cannot simultaneously expand to fit its parent.

我显然误解了这种布局应该如何工作。

这是Scaffold此页面主体现在的示例代码：

new Container(
// Outer container so we can set margins and padding for the cards
// that will hold the rest of the view.
alignment: FractionalOffset.topCenter,
margin: new EdgeInsets.only(top: style.wideMargin),
padding: new EdgeInsets.symmetric(horizontal: style.defaultMargin),
child: new Card(
  child: new Column(
    children: [
      new CustomHeader(), // <-- a Row with some buttons in it
      new Divider(),
      new MaterialList(
        type: MaterialListType.twoLine,
        children: listItems, // <-- a list of custom Rows
      ),
    ],
  ),
),

）

我如何拥有一张紧密包裹Column小部件的卡片？